A so-called spin coating method has been widely known as a method of coating a coating liquid on a substrate such as, for example, a semiconductor wafer or a glass substrate. In the spin coating method, a coating liquid is coated on the surface of the substrate by supplying the coating liquid from a coating nozzle to the central portion of the substrate in a state where the substrate is rotated so that the coating liquid is diffused on the substrate by a centrifugal force.
When the spin coating method is used, the coating liquid supplied to the substrate is diffused with a high speed rotation. Thus, most of the supplied coating liquid is scattered from the peripheral portion of the substrate, thereby being wasted.
Therefore, in order to suppress such waste of the coating liquid, for example, Japanese Patent Laid-Open Publication No. 2011-167603 discloses a method of coating a coating liquid on a substrate by drawing out the coating liquid from an ejecting port of a coating nozzle by a capillary phenomenon. Specifically, a slit-shaped ejecting port formed at the lower end face of the coating nozzle is positioned close to the substrate to maintain the ejecting port and the substrate in a state where a predetermined gap is formed therebetween. In a state where the coating liquid ejected from the ejecting port is brought into contact with the substrate, the substrate and the coating nozzle are relatively moved in the horizontal direction, for example, in the radial direction of the substrate. Then, the coating liquid is drawn out from the ejecting port by the capillary phenomenon and coated on the substrate.